1. Field of the Invention
This invention relates to a process for preparing a family of polymeric orange anthrapyridine colorants.
2. Prior Art
Concurrently filed U.S. Patent Application Ser. No. 751,856 abandoned, of Leonard A. Bunes, entitled Orange Colors, discloses a family of new polymeric anthrapyridine colorants. This application of Bunes discloses that these colorants may be found by (1) synthesizing the anthrapyridine chromophore as a halo-group containing intermediate and (2) coupling the anthrapyridine to an amine-group containing backbone. This method has the advantage of offer ng a very pure orange color and clearly a single chromophore species attached to the polymer backbone. It happens, however, that the polymeric version of the immediate precursors to the anthrapyridines (anthrapyridones) are themselves valuable red colorants. The present invention employs this polymeric precursor and makes it possible to efficiently prepare two colorants together with less effort than is required to prepare them independently.